During a follow-up visit in 2008, biochemical relapse of primary hyperparathyroidism was detected (parathormone (PTH) 163.8 pg/mL, total calcium concentration 2.81 mmol/l) without any visible lesions in ultrasonography or single-photon emission computed tomography/computed tomography (SPECT/CT) with technetium-99 m methoxyisobutylisonitrile (99mTc) Tc-MIBI. The gene discussed is PTH; the disease is primary hyperparathyroidism.